X.25 is the. International Telecommunications Union's recommendation for an interface between a Data Terminal Equipment (DTE) and Data Computing Equipment (DCE) over a Public Data Network. Generally, X.25 covers layers 1 to 3 of the ISO communication model. X.25 is most often carried within LAPB Information (I) frames, which are in turn transported by HDLC physical media operating in asynchronous balanced mode (ABM).
Link Access Protocol Balanced (LAPB) is a layer 2 protocol and is used to carry X.25 packets. In fact, as known by the skilled addressee, the link layer ensures reliable transfer of data by transmitting the data as a sequence of frames. Furthermore, the link layer is used for connection synchronization of the layer 1 physical media in order to ensure that a receiver is in step with a transmitter.
The link layer protocol is further adapted to detect transmission of errors and recovery from such errors as well as identification and reporting of procedural errors to higher layers for recovery.
Now referring to FIG. 1, there is shown how a local LAPB device is configured according to prior art method.
According to step 10, data related to a remote LAPB device to which a local LAPB will be connected is gathered by an operator. The data comprises operating and addressing mode (DTE or DCE), startup mode (active or passive, with or without remote resets), and frame format (modulo-8 or “basic” mode, modulo-128 or “extended” mode, modulo-32768 or “super” mode).
According to step 12, the local LAPB device is configured by the operator. More precisely, the local LAPB device is configured according to the data related to the remote LAPB device configuration gathered according to step 10. The local LAPB device may be configured by the operator as a data computing equipment or as a data terminal equipment. As known by the one skilled in the art, the configuration is performed via a configuration interface.
It will be appreciated that such configuration requires knowledgeable human resources, which is costly.
Moreover, it will be appreciated that such configuration requires the operator to gather information on the remote LAPB device which may be a source of errors as the network may comprise a large number of devices which may render the task cumbersome.
There is a need for a method and apparatus that will overcome the above-identified drawbacks.